‘So it’s at least a few years old. And the phone network was improved a couple of months back: all residential lines got new numbers, didn’t they? If these are phone numbers at all, it looks like they’re out of date. Maybe Lorelei stopped whatever she was doing; or there’s a newer list somewhere.’ I didn’t know what to say; it was crushing. ‘Look, keep trying, but let’s not get our hopes up.’ I nodded and tried again. But there was only the message ‘That number does not exist’ that told me the call would not be answered. Then it was the sixth of seven entries. I read out the number without much hope and heard the familiar silence. Then a clicking. Then the operator’s voice.

‘Connecting you now.’

And then – incredibly – a distant ringing that said we had made a connection. Tibbot punched the air before pressing his ear next to mine so he could hear. We were on tenterhooks, barely daring to breathe in case it somehow caused the line to cut out. It rang and rang.

‘Are they there?’ Tibbot asked, frustrated. ‘Answer the bloody thing.’

After a full minute without an answer, I gently placed the handset back in the cradle and pressed the button to return my money.

‘But it’s better than nothing. I suppose they haven’t had their number changed,’ I said, doing my best to remain positive. I pondered for a second. ‘Is it just residential numbers that changed?’

‘Yes.’

‘So this one might be a business or government number?’

‘Yes,’ he said, nodding. ‘Yes, you might be right. Try it again.’ I hardly needed to be told. Once again, there was silence, clicking and the faint ringing, as if the other telephone were a few metres along the street and we could just reach out and touch whoever was standing beside it. But it rang and rang without a voice coming on. I hung up for the second time. Still excited, I tried the final number, but the result was back to ‘That number does not exist’.

‘We’ll get there,’ Tibbot said. ‘We’ve got one that works. But let’s go and find this Rachel Burton. She’s tied up in this.’

I looked at my watch as we walked quickly towards Blackfriars Station. It was half past three. ‘Where do your colleagues think you are?’ I asked.

‘Looking into some phantom theft of a box of coats from a shop.’

‘Too dull for them to ask you about it?’